Shader used factories/types/pipelines should be in DDC key

A licensee noticed that the ShouldCache types for FLandscapeMaterialResource changed in the 4.18.2 but this did not affect the DDC keys generated. This caused an endless compilation loop where the shader map was considered incomplete but the updated result couldn't be pushed back to the DDC.

• Install and create a project in 4.18.0
• Create a landscape material and apply to a terrain
• Update to 4.18.2
• Note the material now recompiles every time the project is opened

*These are speculative repro steps based on user reports.